Coronavirus Risk Calculators: What You Need to Know
A screenshot of one coronavirus risk calculator.
People in my family seem to develop every ailment in the world, including feline distemper and Dutch elm disease, so I naturally put fingers to keyboard when I discovered that COVID-19 risk calculators now exist.
"It's best to look at your risk band. This will give you a more useful insight into your personal risk."
But the results – based on my answers to questions -- are bewildering.
A British risk calculator developed by the Nexoid software company declared I have a 5 percent, or 1 in 20, chance of developing COVID-19 and less than 1 percent risk of dying if I get it. Um, great, I think? Meanwhile, 19 and Me, a risk calculator created by data scientists, says my risk of infection is 0.01 percent per week, or 1 in 10,000, and it gave me a risk score of 44 out of 100.
Confused? Join the club. But it's actually possible to interpret numbers like these and put them to use. Here are five tips about using coronavirus risk calculators:
1. Make Sure the Calculator Is Designed For You
Not every COVID-19 risk calculator is designed to be used by the general public. Cleveland Clinic's risk calculator, for example, is only a tool for medical professionals, not sick people or the "worried well," said Dr. Lara Jehi, Cleveland Clinic's chief research information officer.
Unfortunately, the risk calculator's web page fails to explicitly identify its target audience. But there are hints that it's not for lay people such as its references to "platelets" and "chlorides."
The 19 and Me or the Nexoid risk calculators, in contrast, are both designed for use by everyone, as is a risk calculator developed by Emory University.
2. Take a Look at the Calculator's Privacy Policy
COVID-19 risk calculators ask for a lot of personal information. The Nexoid calculator, for example, wanted to know my age, weight, drug and alcohol history, pre-existing conditions, blood type and more. It even asked me about the prescription drugs I take.
It's wise to check the privacy policy and be cautious about providing an email address or other personal information. Nexoid's policy says it provides the information it gathers to researchers but it doesn't release IP addresses, which can reveal your location in certain circumstances.
John-Arne Skolbekken, a professor and risk specialist at Norwegian University of Science and Technology, entered his own data in the Nexoid calculator after being contacted by LeapsMag for comment. He noted that the calculator, among other things, asks for information about use of recreational drugs that could be illegal in some places. "I have given away some of my personal data to a company that I can hope will not misuse them," he said. "Let's hope they are trustworthy."
The 19 and Me calculator, by contrast, doesn't gather any data from users, said Cindy Hu, data scientist at Mathematica, which created it. "As soon as the window is closed, that data is gone and not captured."
The Emory University risk calculator, meanwhile, has a long privacy policy that states "the information we collect during your assessment will not be correlated with contact information if you provide it." However, it says personal information can be shared with third parties.
3. Keep an Eye on Time Horizons
Let's say a risk calculator says you have a 1 percent risk of infection. That's fairly low if we're talking about this year as a whole, but it's quite worrisome if the risk percentage refers to today and jumps by 1 percent each day going forward. That's why it's helpful to know exactly what the numbers mean in terms of time.
Unfortunately, this information isn't always readily available. You may have to dig around for it or contact a risk calculator's developers for more information. The 19 and Me calculator's risk percentages refer to this current week based on your behavior this week, Hu said. The Nexoid calculator, by contrast, has an "infinite timeline" that assumes no vaccine is developed, said Jonathon Grantham, the company's managing director. But your results will vary over time since the calculator's developers adjust it to reflect new data.
When you use a risk calculator, focus on this question: "How does your risk compare to the risk of an 'average' person?"
4. Focus on the Big Picture
The Nexoid calculator gave me numbers of 5 percent (getting COVID-19) and 99.309 percent (surviving it). It even provided betting odds for gambling types: The odds are in favor of me not getting infected (19-to-1) and not dying if I get infected (144-to-1).
However, Grantham told me that these numbers "are not the whole story." Instead, he said, "it's best to look at your risk band. This will give you a more useful insight into your personal risk." Risk bands refer to a segmentation of people into five categories, from lowest to highest risk, according to how a person's result sits relative to the whole dataset.
The Nexoid calculator says I'm in the "lowest risk band" for getting COVID-19, and a "high risk band" for dying of it if I get it. That suggests I'd better stay in the lowest-risk category because my pre-existing risk factors could spell trouble for my survival if I get infected.
Michael J. Pencina, a professor and biostatistician at Duke University School of Medicine, agreed that focusing on your general risk level is better than focusing on numbers. When you use a risk calculator, he said, focus on this question: "How does your risk compare to the risk of an 'average' person?"
The 19 and Me calculator, meanwhile, put my risk at 44 out of 100. Hu said that a score of 50 represents the typical person's risk of developing serious consequences from another disease – the flu.
5. Remember to Take Action
Hu, who helped develop the 19 and Me risk calculator, said it's best to use it to "understand the relative impact of different behaviors." As she noted, the calculator is designed to allow users to plug in different answers about their behavior and immediately see how their risk levels change.
This information can help us figure out if we should change the way we approach the world by, say, washing our hands more or avoiding more personal encounters.
"Estimation of risk is only one part of prevention," Pencina said. "The other is risk factors and our ability to reduce them." In other words, odds, percentages and risk bands can be revealing, but it's what we do to change them that matters.
Is a Successful HIV Vaccine Finally on the Horizon?
The HIV virus (yellow) infecting a human cell.
Few vaccines have been as complicated—and filled with false starts and crushed hopes—as the development of an HIV vaccine.
While antivirals help HIV-positive patients live longer and reduce viral transmission to virtually nil, these medications must be taken for life, and preventative medications like pre-exposure prophylaxis, known as PrEP, need to be taken every day to be effective. Vaccines, even if they need boosters, would make prevention much easier.
In August, Moderna began human trials for two HIV vaccine candidates based on messenger RNA.
As they have with the Covid-19 pandemic, mRNA vaccines could change the game. The technology could be applied for gene editing therapy, cancer, other infectious diseases—even a universal influenza vaccine.
In the past, three other mRNA vaccines completed phase-2 trials without success. But the easily customizable platforms mean the vaccines can be tweaked better to target HIV as researchers learn more.
Ever since HIV was discovered as the virus causing AIDS, researchers have been searching for a vaccine. But the decades-long journey has so far been fruitless; while some vaccine candidates showed promise in early trials, none of them have worked well among later-stage clinical trials.
There are two main reasons for this: HIV evolves incredibly quickly, and the structure of the virus makes it very difficult to neutralize with antibodies.
"We in HIV medicine have been desperate to find a vaccine that has effectiveness, but this goal has been elusive so far."
"You know the panic that goes on when a new coronavirus variant surfaces?" asked John Moore, professor of microbiology and immunology at Weill Cornell Medicine who has researched HIV vaccines for 25 years. "With HIV, that kind of variation [happens] pretty much every day in everybody who's infected. It's just orders of magnitude more variable a virus."
Vaccines like these usually work by imitating the outer layer of a virus to teach cells how to recognize and fight off the real thing off before it enters the cell. "If you can prevent landing, you can essentially keep the virus out of the cell," said Larry Corey, the former president and director of the Fred Hutchinson Cancer Research Center who helped run a recent trial of a Johnson & Johnson HIV vaccine candidate, which failed its first efficacy trial.
Like the coronavirus, HIV also has a spike protein with a receptor-binding domain—what Moore calls "the notorious RBD"—that could be neutralized with antibodies. But while that target sticks out like a sore thumb in a virus like SARS-CoV-2, in HIV it's buried under a dense shield. That's not the only target for neutralizing the virus, but all of the targets evolve rapidly and are difficult to reach.
"We understand these targets. We know where they are. But it's still proving incredibly difficult to raise antibodies against them by vaccination," Moore said.
In fact, mRNA vaccines for HIV have been under development for years. The Covid vaccines were built on decades of that research. But it's not as simple as building on this momentum, because of how much more complicated HIV is than SARS-CoV-2, researchers said.
"They haven't succeeded because they were not designed appropriately and haven't been able to induce what is necessary for them to induce," Moore said. "The mRNA technology will enable you to produce a lot of antibodies to the HIV envelope, but if they're the wrong antibodies that doesn't solve the problem."
Part of the problem is that the HIV vaccines have to perform better than our own immune systems. Many vaccines are created by imitating how our bodies overcome an infection, but that doesn't happen with HIV. Once you have the virus, you can't fight it off on your own.
"The human immune system actually does not know how to innately cure HIV," Corey said. "We needed to improve upon the human immune system to make it quicker… with Covid. But we have to actually be better than the human immune system" with HIV.
But in the past few years, there have been impressive leaps in understanding how an HIV vaccine might work. Scientists have known for decades that neutralizing antibodies are key for a vaccine. But in 2010 or so, they were able to mimic the HIV spike and understand how antibodies need to disable the virus. "It helps us understand the nature of the problem, but doesn't instantly solve the problem," Moore said. "Without neutralizing antibodies, you don't have a chance."
Because the vaccines need to induce broadly neutralizing antibodies, and because it's very difficult to neutralize the highly variable HIV, any vaccine will likely be a series of shots that teach the immune system to be on the lookout for a variety of potential attacks.
"Each dose is going to have to have a different purpose," Corey said. "And we hope by the end of the third or fourth dose, we will achieve the level of neutralization that we want."
That's not ideal, because each individual component has to be made and tested—and four shots make the vaccine harder to administer.
"You wouldn't even be going down that route, if there was a better alternative," Moore said. "But there isn't a better alternative."
The mRNA platform is exciting because it is easily customizable, which is especially important in fighting against a shapeshifting, complicated virus. And the mRNA platform has shown itself, in the Covid pandemic, to be safe and quick to make. Effective Covid vaccines were comparatively easy to develop, since the coronavirus is easier to battle than HIV. But companies like Moderna are capitalizing on their success to launch other mRNA therapeutics and vaccines, including the HIV trial.
"You can make the vaccine in two months, three months, in a research lab, and not a year—and the cost of that is really less," Corey said. "It gives us a chance to try many more options, if we've got a good response."
In a trial on macaque monkeys, the Moderna vaccine reduced the chances of infection by 85 percent. "The mRNA platform represents a very promising approach for the development of an HIV vaccine in the future," said Dr. Peng Zhang, who is helping lead the trial at the National Institute of Allergy and Infectious Diseases.
Moderna's trial in humans represents "a very exciting possibility for the prevention of HIV infection," Dr. Monica Gandhi, director of the UCSF-Gladstone Center for AIDS Research, said in an email. "We in HIV medicine have been desperate to find a vaccine that has effectiveness, but this goal has been elusive so far."
If a successful HIV vaccine is developed, the series of shots could include an mRNA shot that primes the immune system, followed by protein subunits that generate the necessary antibodies, Moore said.
"I think it's the only thing that's worth doing," he said. "Without something complicated like that, you have no chance of inducing broadly neutralizing antibodies."
"I can't guarantee you that's going to work," Moore added. "It may completely fail. But at least it's got some science behind it."
New Podcast: The Lead Scientist for the NASA Mission to Venus
The volcano Sapas Mons is displayed in the center of this computer-generated three-dimensional perspective view of the surface of Venus.
The "Making Sense of Science" podcast features interviews with leading medical and scientific experts about the latest developments and the big ethical and societal questions they raise. This monthly podcast is hosted by journalist Kira Peikoff, founding editor of the award-winning science outlet Leaps.org.
This month, our guest is JPL's Dr. Suzanne Smrekar, who will be pushing the boundaries of knowledge about the planet Venus during the upcoming VERITAS mission set to launch in 2028. Why did Earth's twin planet develop so differently than our own? Could Venus ever have hosted life? What is the bigger purpose for humanity in studying the solar system -- is it purely scientific, or is it also a matter of art and philosophy? Hear Dr. Smrekar discuss all this and more on the latest episode.
Watch the 30-Second Trailer:
Listen to the Episode:
Kira Peikoff was the editor-in-chief of Leaps.org from 2017 to 2021. As a journalist, her work has appeared in The New York Times, Newsweek, Nautilus, Popular Mechanics, The New York Academy of Sciences, and other outlets. She is also the author of four suspense novels that explore controversial issues arising from scientific innovation: Living Proof, No Time to Die, Die Again Tomorrow, and Mother Knows Best. Peikoff holds a B.A. in Journalism from New York University and an M.S. in Bioethics from Columbia University. She lives in New Jersey with her husband and two young sons. Follow her on Twitter @KiraPeikoff.